1. Field of the Invention
The present invention relates to a tire slip-preventing construction formed on a floor plate, and more particularly to a tire slip-preventing construction formed on a floor plate to be installed as the floor surface of a second floor of a self-running type sky parking-place or as the surface of a road being repaired.
2. Description of the Prior Art
A sky parking-place of self-running type is constructed with a plurality of pillars standing on the ground. H-sections are installed X-direction (lengthwise and widthwise directions) and Y-direction (vertical direction) on upper portions of the pillars. A plurality of flat or flat long floor plates are installed on horizontal spaces surrounded with the H-sections in such a manner that the floor plates cover the spaces. In this manner, the floor surface of a second floor of the sky parking-place is constructed. A plurality of projections is formed on the upper surface of the floor plates to prevent tires of cars from slipping thereon on rainy days in particular.
FIG. 14 is a perspective view, with a principal portion broken away in section, showing an example of a conventional tire slip-preventing construction formed on a floor plate. FIG. 15 is a sectional view showing a principal portion of the floor plate of the tire slip-preventing construction shown in FIG. 14. A plurality of projections 2 for preventing a tire slip is formed on the upper surface of a floor plate 1. The projection 2 is approximately semicircular in section. Although only one projection 2 is shown in FIGS. 14 and 15, a plurality of projections 2 are formed on the upper surface of the floor plate 1.
FIG. 16 is a perspective view, with a principal portion broken away, showing another example of a conventional tire slip-preventing construction formed on a floor plate. FIG. 17 is a sectional view showing a principal portion of the floor plate of the tire slip-preventing construction shown in FIG. 16. A plurality of circular holes 3 is formed on the floor plate 1 by burring to form a plurality of approximately ring-shaped projections 4 on the floor plate 1. In some conventional tire slip-preventing constructions, the hole 3 is elliptic or slot-shaped. The floor plate 1 shown in FIG. 16 prevents tires from slipping thereon by means of the projections 4.
FIG. 18 is a sectional view showing another example of a conventional tire slip-preventing construction formed on a floor plate. A plurality of projections 5 approximately semicircular in section is formed on the upper surface of the floor plate 1. The height of the projection 5 is greater than that of the above-described projections 2 and 4. One side of the projection 5 is integral with the floor plate 1 while the other side thereof is not connected with the floor plate 1. That is, the thickness of the projection 5 is set to be greater than that of the floor plate 1 so as to prevent a tire slip effectively.
As described above, projections in various configurations are formed on the upper surface of a floor plate so as to prevent a tire from slipping thereon.
The above-described conventional tire slip-preventing constructions have the following problems:
That is, because the projection 2 of the conventional tire slip-preventing construction shown in FIGS. 14 and 15 is approximately circular, the coefficient of friction of the projection 2 is low. Therefore, tires are apt to slip on the floor plate 1 on rainy days in particular. That is, the tire slip-preventing construction hardly perform its function.
In the conventional tire slip-preventing construction shown in FIGS. 18 and 17, in order to allow the tire slip-preventing construction to perform its function very efficiently, the periphery of the projection 4 forms a large angle with the upper surface of the floor plate 1 to make the projection 4 high. Therefore, in curving the periphery of the projection 4, the periphery is cracked because stress is generated in the periphery of the projection 4. As a result of repeated collisions between tires and the projection 4, the projection 4 is cracked in a greater extent, with the result that the projection 4 is broken. That is, the tire slip-preventing construction becomes unfunctional. Further, the breakage of the projection 4 leads to the cracking of the floor panel 1.
Moreover, because a plurality of holes 3 are formed on the floor panel 1, rain drops downstairs through the holes 3.
Because the projection 4 is formed by burring, the upper edge thereof is pointed as shown in FIG. 17. There is a great possibility that tires are damaged by the projection 4 when a handle of a car is turned to start the car, with tires placed on the projections 4, because power steering is adopted in most of cars in recent years. If the collisions between the tires and the projection 4 are repeated, the tires are cracked, and thus they are punctured.
In the conventional tire slip-preventing construction shown in FIG. 18, the projection 5 is approximately semicircular and the height thereof is greater than that of the projections 2 and 4. Thus, the tire slip-preventing construction is superior to those shown in FIGS. 14 through 17 in the function of preventing tires from slipping.
Because the height of the projection 5 is great, the projection 5 causes a car to be shaken vertically in a great extent when a car travels on the projection 5. As a result, the car bounds and the entire floor plate 1 is shaken, which causes the floor surface to be shaken. Consequently, great noises are generated, thus giving nuisance to people in the neighborhood at night in particular. In addition, as shown in FIG. 18, rainwater drops downstairs through a gap 6 between the projection 5 and the upper surface of the floor plate 1.